Constant current transformer



Manin@ 29 R. A. JQHNSQN 2,33%315 CONSTANT CURRENT TRNSFORMER Filed OO'.. 3l, 1941 Patented Mar. 2, 1943 UNITED STATES PATENT OFFICE CONSTANT CURRENT TRANSFORMER Richard A. S. Johnson, Chicago, Ill.

Application October 31, 1941, Serial No. 417,332

6 Claims.

This invention relates to improvements in constant current transformers or regulators which may be utilized for providing current for various purposes, but particularly for street-lighting or other similar commercial uses. Heretoiore moving-coil constant current transformers have been commonly used, but such transformers have various objectionable features which are well known to those familiar with such apparatus.

Other transformers have also been proposed embodying the use of the monocyclic square and while such systems have certain inherent advantages, they have failed to be wholly successful or to solve the problem. The present invention is directed particularly to such monocyclic square transformers or regulators and provides means for overcoming the objectionable features heretof ore present in such systems.

The objects of this invention are to provide an improved apparatus or system whereby constant potential alternating current may be transformed or changed to a constant current which will have approximately no variation and which will be particularly adapted for street-lighting or other similar uses; to provide a constant current transformer which will be simple in construction and particularly eective in operation; and to provide an apparatus or system having such further advantages and improvements as will be set forth more fully hereinafter. The accompanying drawing shows a diagrammatic View of a preferred form of my invention.

As shown in the drawing, the constant potential supply wires or lines I and 2 are connected in the usual manner to the monocyclic square designated generally by the numeral 3. Two sides of the square are provided with capacitors 4 and 5 and the opposite sides with reactors 6 and l. The output from the monocyclic square is through wires 8 and y9 which are also connected with the monocyclic square in the usual manner. The wire or line 8 is connected with one terminal of an autotransformer Ill. The opposite terminal of the autotransformer is connected by wire II with a primary coil I2 of a saturation transformer I3. The core I 4 of the transformer may be shaped in any suitable manner, but as shown, is of rec-- tangular form with two transverse legs or crosspieces I and IS. The leg or cross-piece I6 is connected to the end of the frame or main core piece I4 by another leg or longitudinal member Il. The coil I2 is mounted on one end or leg of the main core I4 and is connected by means of wire I8 with a second primary coil I9 mounted on the leg I5 which in turn is connected by means of wire 2U with a third primary coil 2| mounted on one end or section of the leg I6. The coil 2| is connected by wire 22 with a fourth primary coil 23 which is mounted on the opposite end of the leg I6 as shown, and which is connected with the wire 9. The primary circuit then is wire 8, autotransformer I0, Wire II, coil I2, wire I8, coil I9, wire 20, coil 2I, wire 22, coil 23, and back through wire 9.

The constant current load circuit is shown as comprising the wires or conductors 24 and 25 and the lamps 26. The wire or conductor 24 is connected with a secondary winding or coil 21 of the saturation transformer I3. This coil is mounted on the end of the core adjacent to the coil I2 and is connected by wire 28 with another coil 29 on the cross-piece or leg I5. The coil 29 is connected by a wire 30 with a coil 3I mounted on the leg I6 adjacent to the coil 2I. The coil 3l is connected by wire 32 with a, coil 33 mounted on the leg I6 adjacent to the coil 23. The coil 33 is connected to the wire 25 as shown. 'The constant current load circuit is from coil 2l through wire 28, coil 28, wire 3D, coil 3|, wire 32, coil 33 and through the connecting conductors to the load.

The wire or conductor 8 is connected by means of a wire 34 with one terminal 35 of an oxide rectifier 3B. Another terminal or connection 3l of the rectifier is connected by wire 38 with theirv wire II thus connecting the rectifier in shunt` around the autotransformer I0. Another terminal or connection 39 of the rectifier 36 is connected by a wire 40 with a coil or winding 4I on the leg or branch II of the saturating transformer I3. The opposite end of the coil 4I is connected by a wire 42 with another terminal 43 of the oxide rectifier 36.

When the apparatus or monocyclic-network regulator is supplied with alternating constant potential current through the supply lines I and 2, and if there is any variation in the voltage, the current in the output lines 8 and 9 will vary in substantially the same proportions. However, the construction and operation of the other parts of the system as shown and described is such that any variation in lines 8 and 9 is overcome and constant current is delivered to the constant current output lines 24 and 25 and consequently constant current is provided for the load 25. Since the current traverses the autotransformer I0, it causes the current to vary in the oxide rectifier 36. The direct current from this oxide rectifier will traverse the saturation winding 4I of the transformer I3 proportionately to the variation of the supply voltage. The primary coils I2, I9, 2I and 23 of the saturating transformer I3 are so positioned in relation to the secondary windings 21, 29, 3I and 33 o f the transformer I3 and the cooperation or eii'ect produced by the coil 4I is such that constant current output in the lines 24 and 25 to the load 26 will be held constant even though there is a variation in the primary voltage.

While I have shown a diagrammatic illustration of the invention, the principles embodied therein are well understood by those familiar with the art and the invention may be embodied in various forms of construction in order to provide commercial apparatus, all of which will come within the scope of the invention as set forth in the following claims in which I claim:

1. The combination with a monocyclic square regulator, a rectifier which receives current from the output of th monocyclic square, and output transformer and a coil operatedly associated with the output transformer and receiving direct current from the rectier whereby the output of the transformer will be controlled by the current from the rectifier and constant current will be delivered from the transformer.

2. In an apparatus of the character set forth,

the combination of a monocyclic square, means forv supplying constant voltage current, to the square, a transformer, output conductors leading from the square to primary coils of the transformer, an auto-transformer connected with one of said output conductors, an oxide rectifier, connections from the rectier leading to the conductor on either side of the auto-transformer, a coil in the output transformer and connections from the coil to the rectier whereby the coil will receive direct current from the rectiier, the arrangement being such that constant current will be delivered from the secondary coils ofthe transformer to the load.

3. The combination of a monocyclic square regulator, means for supplying constant voltage current to the regulator, a transformer including a core having a plurality of primary coils, a circuit from the regulator to the primary coils for the output current of the regulator, a coil in the transformer, means for converting a. portion of said output current into direct current and supplying the same to the last named coil to affect the ux of the transformer, secondary coils mounted on the transformer adjacent to the primary coils, ay", circuit from the secondary coils, and a load connected with said circuit.

4. In combination with a monocyclic square, a

current transformer, an oxide rectifier and a regulating transformer having a control coil, said current transformer having its primary. in series circuit relation between said monocyclic square and said current transformer, the secondary of said current transformer being connected to said rectier the output circuit of which being connected to the control coil of said regulating transformer in a manner to hold the current substantially constant in the output circuit of said regu.- lating transformer.

' 5. In combination with a constant current transformer, an auto-transformer, a rectier, a regulating transformer having a direct current control coil and a constant current loadvclrcuit, said constant current transformer being connected to said. regulating transformer, and said auto-transformer being connected in series circuit relation between said constant current transformer and said regulating transformer, with the output circuit of said ,auto-transformer connected to the input circuit of said reotier and having the .output circuit of said rectifier co'nnected to said direct current control coil of said regulating transformer in a manner to hold the current constant in said constant current load circuit.

6. In combination with a resonant circuit constant current regulator, a current transformer having a primary and a secondary, a rectiier, a saturating regulating transformer having a direct current control coil and a constant current load circuit, said resonant circuit constant current regulator having its output circuit connected tothe input circuit of said saturating regulating transformer and said current transformer having its input circuit in series circuit relation between said resonant circuit, constant current regulator and said saturating regulating transformer and the output circuit of said current transformer being connected to the input circuit of said rectier, and the output circuit of said rectier being connected to the direct current control coil of said regulating transformer ina manner to hold the current constant in said constant current load circuit.

RICHARD a s. JOHNSON. 

